Belda Ignacio, Ruiz Javier, Alastruey-Izquierdo Ana, Navascués Eva, Marquina Domingo, Santos Antonio
Department of Microbiology, Biology Faculty, Complutense University of Madrid Madrid, Spain.
Mycology Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III Madrid, Spain.
Front Microbiol. 2016 Jan 20;7:12. doi: 10.3389/fmicb.2016.00012. eCollection 2016.
Non-Saccharomyces yeasts are a heterogeneous microbial group involved in the early stages of wine fermentation. The high enzymatic potential of these yeasts makes them a useful tool for increasing the final organoleptic characteristics of wines in spite of their low fermentative power. Their physiology and contribution to wine quality are still poorly understood, with most current knowledge being acquired empirically and in most cases based in single species and strains. This work analyzed the metabolic potential of 770 yeast isolates from different enological origins and representing 15 different species, by studying their production of enzymes of enological interest and linking phylogenetic and enzymatic data. The isolates were screened for glycosidase enzymes related to terpene aroma release, the β-lyase activity responsible for the release of volatile thiols, and sulfite reductase. Apart from these aroma-related activities, protease, polygalacturonase and cellulase activities were also studied in the entire yeast collection, being related to the improvement of different technological and sensorial features of wines. In this context, and in terms of abundance, two different groups were established, with α-L-arabinofuranosidase, polygalacturonase and cellulase being the less abundant activities. By contrast, β-glucosidase and protease activities were widespread in the yeast collection studied. A classical phylogenetic study involving the partial sequencing of 26S rDNA was conducted in conjunction with the enzymatic profiles of the 770 yeast isolates for further typing, complementing the phylogenetic relationships established by using 26S rDNA. This has rendered it possible to foresee the contribution different yeast species make to wine quality and their potential applicability as pure inocula, establishing species-specific behavior. These consistent results allowed us to design future targeted studies on the impact different non-Saccharomyces yeast species have on wine quality, understanding intra and interspecific enzymatic odds and, therefore, aiming to predict the most suitable application for the current non-Saccharomyces strains, as well as the potential future applications of new strains. This work therefore contributes to a better understanding of the concept of wine microbiome and its potential consequences for wine quality, as well as to the knowledge of non-Saccharomyces yeasts for their use in the wine industry.
非酿酒酵母是参与葡萄酒发酵早期阶段的一类异质微生物群体。尽管这些酵母的发酵能力较低，但其高酶活性使其成为提升葡萄酒最终感官特性的有用工具。人们对它们的生理学特性及其对葡萄酒品质的贡献仍知之甚少，目前的大多数知识都是通过经验获得的，而且在大多数情况下基于单一物种和菌株。本研究通过研究770株来自不同酿酒学来源、代表15个不同物种的酵母分离株产生的具有酿酒学意义的酶，并将系统发育数据与酶学数据相联系，分析了它们的代谢潜力。对这些分离株进行了与萜烯香气释放相关的糖苷酶、负责挥发性硫醇释放的β-裂解酶活性以及亚硫酸盐还原酶的筛选。除了这些与香气相关的活性外，还对整个酵母菌株库中的蛋白酶、多聚半乳糖醛酸酶和纤维素酶活性进行了研究，这些活性与葡萄酒不同工艺和感官特性的改善有关。在这种情况下，从丰度方面建立了两个不同的组，α-L-阿拉伯呋喃糖苷酶、多聚半乳糖醛酸酶和纤维素酶活性较低。相比之下，β-葡萄糖苷酶和蛋白酶活性在研究的酵母菌株库中广泛存在。结合770株酵母分离株的酶谱，对26S rDNA进行部分测序，开展了一项经典的系统发育研究，以进一步分型，补充利用26S rDNA建立的系统发育关系。这使得预测不同酵母物种对葡萄酒品质的贡献及其作为纯接种物的潜在适用性成为可能，确立了物种特异性行为。这些一致的结果使我们能够设计未来有针对性的研究，以了解不同非酿酒酵母物种对葡萄酒品质的影响，了解种内和种间的酶学差异，从而旨在预测当前非酿酒酵母菌株的最合适应用以及新菌株未来的潜在应用。因此，这项工作有助于更好地理解葡萄酒微生物组的概念及其对葡萄酒品质的潜在影响，也有助于了解非酿酒酵母在葡萄酒工业中的应用知识。
